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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-06 01:02:30 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-06 01:02:30 +0000
commit76cb841cb886eef6b3bee341a2266c76578724ad (patch)
treef5892e5ba6cc11949952a6ce4ecbe6d516d6ce58 /drivers/mmc/core/pwrseq_emmc.c
parentInitial commit. (diff)
downloadlinux-upstream.tar.xz
linux-upstream.zip
Adding upstream version 4.19.249.upstream/4.19.249upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'drivers/mmc/core/pwrseq_emmc.c')
-rw-r--r--drivers/mmc/core/pwrseq_emmc.c121
1 files changed, 121 insertions, 0 deletions
diff --git a/drivers/mmc/core/pwrseq_emmc.c b/drivers/mmc/core/pwrseq_emmc.c
new file mode 100644
index 000000000..154f4204d
--- /dev/null
+++ b/drivers/mmc/core/pwrseq_emmc.c
@@ -0,0 +1,121 @@
+/*
+ * Copyright (C) 2015, Samsung Electronics Co., Ltd.
+ *
+ * Author: Marek Szyprowski <m.szyprowski@samsung.com>
+ *
+ * License terms: GNU General Public License (GPL) version 2
+ *
+ * Simple eMMC hardware reset provider
+ */
+#include <linux/delay.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/platform_device.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/gpio/consumer.h>
+#include <linux/reboot.h>
+
+#include <linux/mmc/host.h>
+
+#include "pwrseq.h"
+
+struct mmc_pwrseq_emmc {
+ struct mmc_pwrseq pwrseq;
+ struct notifier_block reset_nb;
+ struct gpio_desc *reset_gpio;
+};
+
+#define to_pwrseq_emmc(p) container_of(p, struct mmc_pwrseq_emmc, pwrseq)
+
+static void mmc_pwrseq_emmc_reset(struct mmc_host *host)
+{
+ struct mmc_pwrseq_emmc *pwrseq = to_pwrseq_emmc(host->pwrseq);
+
+ gpiod_set_value_cansleep(pwrseq->reset_gpio, 1);
+ udelay(1);
+ gpiod_set_value_cansleep(pwrseq->reset_gpio, 0);
+ udelay(200);
+}
+
+static int mmc_pwrseq_emmc_reset_nb(struct notifier_block *this,
+ unsigned long mode, void *cmd)
+{
+ struct mmc_pwrseq_emmc *pwrseq = container_of(this,
+ struct mmc_pwrseq_emmc, reset_nb);
+ gpiod_set_value(pwrseq->reset_gpio, 1);
+ udelay(1);
+ gpiod_set_value(pwrseq->reset_gpio, 0);
+ udelay(200);
+
+ return NOTIFY_DONE;
+}
+
+static const struct mmc_pwrseq_ops mmc_pwrseq_emmc_ops = {
+ .reset = mmc_pwrseq_emmc_reset,
+};
+
+static int mmc_pwrseq_emmc_probe(struct platform_device *pdev)
+{
+ struct mmc_pwrseq_emmc *pwrseq;
+ struct device *dev = &pdev->dev;
+
+ pwrseq = devm_kzalloc(dev, sizeof(*pwrseq), GFP_KERNEL);
+ if (!pwrseq)
+ return -ENOMEM;
+
+ pwrseq->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
+ if (IS_ERR(pwrseq->reset_gpio))
+ return PTR_ERR(pwrseq->reset_gpio);
+
+ if (!gpiod_cansleep(pwrseq->reset_gpio)) {
+ /*
+ * register reset handler to ensure emmc reset also from
+ * emergency_reboot(), priority 255 is the highest priority
+ * so it will be executed before any system reboot handler.
+ */
+ pwrseq->reset_nb.notifier_call = mmc_pwrseq_emmc_reset_nb;
+ pwrseq->reset_nb.priority = 255;
+ register_restart_handler(&pwrseq->reset_nb);
+ } else {
+ dev_notice(dev, "EMMC reset pin tied to a sleepy GPIO driver; reset on emergency-reboot disabled\n");
+ }
+
+ pwrseq->pwrseq.ops = &mmc_pwrseq_emmc_ops;
+ pwrseq->pwrseq.dev = dev;
+ pwrseq->pwrseq.owner = THIS_MODULE;
+ platform_set_drvdata(pdev, pwrseq);
+
+ return mmc_pwrseq_register(&pwrseq->pwrseq);
+}
+
+static int mmc_pwrseq_emmc_remove(struct platform_device *pdev)
+{
+ struct mmc_pwrseq_emmc *pwrseq = platform_get_drvdata(pdev);
+
+ unregister_restart_handler(&pwrseq->reset_nb);
+ mmc_pwrseq_unregister(&pwrseq->pwrseq);
+
+ return 0;
+}
+
+static const struct of_device_id mmc_pwrseq_emmc_of_match[] = {
+ { .compatible = "mmc-pwrseq-emmc",},
+ {/* sentinel */},
+};
+
+MODULE_DEVICE_TABLE(of, mmc_pwrseq_emmc_of_match);
+
+static struct platform_driver mmc_pwrseq_emmc_driver = {
+ .probe = mmc_pwrseq_emmc_probe,
+ .remove = mmc_pwrseq_emmc_remove,
+ .driver = {
+ .name = "pwrseq_emmc",
+ .of_match_table = mmc_pwrseq_emmc_of_match,
+ },
+};
+
+module_platform_driver(mmc_pwrseq_emmc_driver);
+MODULE_LICENSE("GPL v2");